There
are
some
specific
characteristics
related
to
a
four
cycle
engine
Two
complete
revolutions
of
the
crankshaft
per
cycle
results
in
a
power
impulse
every
other
revolution.
These
engines
are
more
popular
than
2
cycle
They
do
require
more
parts
that
2
cycle.
Less
exhaust
emissions
than
2
cycle.
Typical
lubrication
system
restricts
angle
of
operation
due
to
either
splash
lube
from
the
sump,
or
pressure
lubricated,
pulling
oil
from
the
sump.
They
are
also
normally
more
durable
than
2
cycle.